1. Field
The present application relates to a measuring device and a measuring method measuring a hollow shape of an object.
2. Description of the Related Art
Conventionally, a distance sensing method or a grazing incidence optics system method has been known as a method for measuring a hollow shape of an object contactlessly. For example, the distance sensing method projects a laser light to the inside of a hollow shape, measures a shift of a reflected light while rotating an object, and measures the hollow shape of the object (e.g., refer to Patent Document 1: Japanese Unexamined Patent Application Publication No. 2006-38820).
Further, measurement of a hollow shape provided in a metal or the like is performed by a method of rotating and moving up-and-down a sensing pin station while putting a sensing pin to the inside surface of the hollow shape using a sensing pin method three-dimensional shape measuring device (e.g., refer to Patent Document 2: Japanese Unexamined Patent Application Publication No. H6-337215).
Alternatively, a method, which detects edges corresponding to both ends of a diameter by a slit optical projection method, is known as a device for measuring a hollow shape without contact (e.g., refer to Patent Document 3: Japanese Unexamined Patent Application Publication No. H8-233545).
The conventional distance sensing method cannot obtain circumference shape information of a hollow shape of an object at one time and requires rotation of the object or a light source, which makes the device complicated and also causes a problem in accuracy.
Further, the method of moving the sensing pin station has a problem of requiring a long measurement time because of the required rotation and up-and-down movement of the sensing pin for measuring the whole hollow shape, and also a problem of possibly causing an error by an effect of eccentricity or deflection in the rotation of the sensing pin station.
Still further, the slit optical projection method requires a slit to be disposed so as to be orthogonal against a measurement direction, and has a problem that the method is not suitable for obtaining a shape by measuring in many directions, since only one direction is measured at one-time. Further, there is also a restriction that the hollow shape of the measuring object should be a through-hole.
The embodiments of the present invention aim at providing a measuring device and a measuring method measuring a hollow shape in a high accuracy with little error with a simple configuration and without a complicated computation.